Trying to figure out kids in matchmaking

I was recently playing a game of rumble hardcore ( stats ) and I placed 2nd in the game.  Now this is probably the first time Ive ever earned a Rampage in Matchmaking.  Not everyday I can go 15 kills without dying.  I can get 10 and right up to the 15 kill mark, but not to it.  I usually play with good players, so its a rarity almost.  Now I killed a guy in the Snipe 2 area who had a shotgun.  I picked it up, crouched down right above the doorway from snipe 1 so that I was centrally located in the snipe tower no matter which way they came from.  Now I received this just by shotty + beatdowns.  So towards the end of the game the guy who placed 3rd starts talking shit to me because pretty much all my kills were with the shotty.  This same guy before the game was saying "I cant even get an experience points for this game" due to him being a higher level than anyone.  So he continually makes comments towards me about how I was garbage because I used a different weapon other than what I started with.  Maybe it was cheap, but a kill is a kill.  Now there are only 7 players Im going against.  15 kills doing the same thing.  Now when in a game do you decide to stop going a certain way.  I mean how many times do I have to kill them to establish that Im in the snipe tower with a shotty.  So do kids get mad if you outsmart them?  I wasnt do anything extrordinary, but it was working for me.  I dont understand why people get mad over things like this in a game.  I mean its the same as when people run around with the sword, and whip it out at the last second to kill someone.  9 times out of 10 youll hear that player say something stupid.  I mean who will honestly sit here and say they wouldnt pick up the sword if they ran across it?  I think if more people would educate themselves on the game, and how to play it..... there would be less people getting mad.  Its really easy to kill most of the time.  You just have to put yourself in an area where your weapon does the most damage.  If youre a smarter player though youll figure out what areas you do good in, and which ones you dont on each map.  Once you learn an area youll know what weapons do you good.